Fluid treating apparatus for yarns



Aug. 5, 1947. 'r. JACKSON ETAL 7 A FLUID TREATING APPARATUS FOR YARNS Filed Jilly 1'1, 194:

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.- Inventors Patented 5, 1947 FLUID TREATlN G APPARATUS FOR YARNS Thomas Jackson and Frank Brentnall Hill, Spondon, near Derby, England, asslgnors to British Celanese Limited, London, England, a

company of Great Britain Application.- July 17, 1943, Serial No. 495,095 In Great BrltainJuly 11, 1942 2 Claims. 1

This invention is concerned with improvements in or relating to the treatment of yarns and similar materials and particularly with improvements in'processes and apparatus for the treatment of yarns and similar materials in a substantially closed chamber with fluids during their travel from one point to another. The application is a continuation-in-part of our. U. S. application S. No. 472,460, filed January 15, 1943.

The known apparatus for the treatment of yarns and similar materials with fluids during their travel from one point to another comprise a substantially closed chamber, into which the materials pass through orifices which have dimensions only slightly greater than those of the crosssections of the materials in order to reduce loss of treatment fiuidas far as possible. With such apparatus it is necessary, each time that a fresh batch of materials is to be treated, to open up the apparatus sufficiently to make it possible to pass the materials through the orifices by hand.

This involves loss of treatment fluid and also loss of heat when the operation is one carried out at a superatmospheric temperature, particularly if it is necessary to allow the apparatus to cool before it can be handled. Moreover, it takes up the time of the operatives and involves an extra overhead charge on account of loss of output while the apparatus is standing idle.

The present invention relates to an improved fluid treatment apparatus which is much simpler to thread up than the known apparatus. The apparatus comprises a substantially closed chamber for treatment fluid having an inlet and an outlet for the materials and provided with means for setting up an induced fluid current into the chamber through the inlet by which the materials enter the chamber. The invention also includes processes for the treatment of yarns and similar materials with fluids during their travel through a substantially closed chamber wherein threading up of the fluid treatment apparatus is assisted by an induced fluid current through the inlet into the chamber.

In general the means for producing the induced current is combined with the inlet, the combination comprising an inlet for the materials and one or more passages through which a fluid current can be forced and which will direct the current so that it sets up an induced fluid current through the inlet. The combination thus resembles an injector and will be referred to by this name in the specification. A number of passages may be disposed'around the inlet for the purpose of directing the current of inducing fluid but u 2 preferably a single annular passage isprovided.

The invention is of chief importance in connection with the stretching of artificial yarns having a basis of an organic derivative of cellulose. As is well-known, the tenacity of such artiflcial yarns can be increased by stretching them in the presence ,of a stretch-assisting agent, which is usually a softening agent, one of the most important methods of stretching such materials being based upon the use of wet steam under pressure as the softening agent. Such a process has been described in U. S. Patent No. 2,142,722, which describes stretching operations carried out while the yarns pass through a sub- 5 stantially closed chamber containing wet steam and provided with an inlet and an outlet for the yarns.

In stretching yarns of an organic derivative of cellulose in wet steam in a'substantially closed chamber, as is described in the above specification a current of steam issues from the yarninlet in a direction opposite to that of the travel of the yarns. This current exerts a tension on the softened yarns in the stretching chamber and it was found that the properties of the stretched yarns could be improved by reducing or eliminating this tension, particularly when the yarns were stretched to a considerable extent, e. g.. to ten or twenty times their original length. Apparatus by means of which this tension may be reduced or avoided is described in U." S. Patent No. 2,142,910 and comprises an and pressure chamber containing a feed device for the yams. The preferred form of apparatus in accordance with the present invention provides a means of attaining the same result in a simpler manner and avoiding the necessity for an end chamber.

The preferred form of apparatus comprises a substantially closed stretching chamber which is provided with a specialform of injector which is provided with means for feeding water into the inlet for the materials. The'injectorthus serves both as a yarn inlet which can be threaded up automatically as described above and also for the introduction, continuously with stretching, of a stream of water in contact with the yarn. This stream of water prevents steam from blowing back through the inlet and thereby avoids any 0 tension opposing the travel of the yarn due to a the steam in contact with the yarn is wet. Preferably the injector comprises a central tube,

through which the yarnpasses and which is provided with a water inlet, and an annular passage counter-current of steam. It also ensures that 4 surrounding the central tube through which air I length and in diameter.

acaaosv or other fluid can be blown to produce an injector action and draw air from the atmosphere through the central tube into the stretching chamber. The injector may, for example, be 1-3 inches in A stretching chamber may be provided with a number of injectors so that a numbercf ends of yarn can be stretched, but it is preferred to have only one injector in a chamber and the invention will be specifically described in connection with this form.

Apparatus in accordance with the present invention may be provided with an outlet for a yarn or similar material which consists merely of a hole drilled in the wall of the chamber opposite to that in which the inlet is located. The invention, however, also includes an improved form of outlet which still further facilitates the threading-up of the apparatus. According to this feature of the invention the outlet is formed in a detachable plug which is screwed or otherwise fixed in a socket in a wall or the chamber, the size of the socket being such that when an end of the material has been introduced into the chamber the end can be taken up by hand or by means of a hook or other device and drawn through the socket. It is then threaded through the outlet in the plug and the plugv replaced in its socket. If the stretching chamber is sufficiently short and the socket into which the plug fits large enough, the induced air current may be suificient to carry the material out through the socket into the atmosphere, which still further facilitates the threading-up operation.

One form of apparatus according to the invention is illustrated in cross-section in the accompanying drawing. The apparatus comprises a stretching chamber 1 having an injector at one end which is made up of the three members 2, 6 and l. The member 2 is provided with a threaded socket 3 into which a connection for air or for steam can be screwed and with another threaded socket 3' for connecting the member I to a supply of water. The socket 3 communicates with an annular channel 4 which itself communicates with an annular orifice 5. formed by an inner face of the member 2 and an outer face of the member 6, which screws into member" 2. The inlet for the yarn or similar material is constituted by orifices formed in the member 6 and the member I, which also screws into the member 2. Member I, which is widely flared on the face exposed to the atmosphere, is provided with a shoulder 8 which abuts against the member 2 and with a nipple 9 having an Orifice In for the passage of the yarn. This nipple projects in the cavity ll formed in member 6, this cavity terminating in an orifice I2 through which the yarn enters the stretching chamber. The position of orifice 12 in relation to the annulus can be adjusted to obtain the maximum suction effect through l2 by slightly withdrawing or advancing the member 6;

. At the opposite end of the chamber is provided a threaded plug I3 which screws into a socket in the wall of the chamber and in which the outlet I4 is formed.

In order to obtain full advantage of the automatic threading-up device it is important that the inlet should be short in the direction of travel of the materials, and that its cross-sectional area should be large, relative to that of the materials, over the major portion of its length, otherwise the induced current may not be strong enough to carry the materials into the chamber and trouble may be experienced owing to their sticking to the sides of the inlet.

The design of injector illustrated in the accompanying drawing fulfills the requirements very well. The length of the inlet, i. e., the distance between the point at which the yarn leaves the atmosphere and that at which it enters the chamber, is short, about 1 /2", and except through the nipple Ill and near the orifice [2 the cross-sectional area of the inlet is very much greater than that of the material to be stretched. Moreover, the nipple l0 helps considerably in directing the material through the orifice l2. As the members i and I are separate it isipossible, if necessary, to remove member I and thread it by hand, then to replace it and complete the threading up through orifice I! by an induced air current. Usually, however, this is not necessary and it is sufllcient to present an end of the yarn or other material to the induced air current flowing into the orifice ID for the material to be carried through the inlet into the chamber. Moreover if the chamber is short enough, e. g., 6 inches, and the socket for the plug. l3 large enough, e. g., /2 inch diameter, the material is usually carried right through the chamber and out through the socket. It can then be threaded through the orifice l4 and the plug l3 replaced in its socket.

The treatment of yarns and similar materials according to the present invention will now be described with particular reference to the stretching of yarn made of acetone-soluble cellulose acetate in wet steam, using the apparatus illustrated in the accompanying drawing in combination with positively driven feed devices for feeding the yarn into and drawing it out of the stretching chamber and controlling the degree of stretch.

The apparatus is first connected up to a water supply through the connection 3' and to supplies of compressed air and wet steam through the connection 3, valves or the like for controlling inlet, after which it is threaded through the outlet l3 in the plug [4. The plug is then replaced in its socket and the yarn led to the second feed device and thence to a take-up mechanism. As

stated above, if the path of the yarnthrough the stretching chamber issuiiiciently short the current of air from the injector may be sufiioient to carry the yarn through the plug socket into the external atmosphere. If not the yarn must be drawn through the socket by hand.

When threading-up of the apparatus has been completed the feed devices are set in motion so that the, yarn is drawn through the stretching chamber, the air current through the annular passage is shut off and steam introduced through the passage. Thevalve on the Water feed is opened and water passed through the connection 3' into the central tube where it comes into contact with the yarn. The yarn thus emerges from the injector carrying with it a film of water and comes immediately into contact with steam, It is thus brought very rapidly from an unsoftened condition to a softened condition in which it is suitable for stretching, and, moreover, any risk oi its coming into contact with patches of dry steamiseliminated.

When starting up the stretching operation, as the steam temperature rises and the yarn becomes softened, the ratio of the speed of the second feed device to that of the first feed device should be increased until the required degree of a stretch is obtained, after which the ratio is mainthose of the inlet orifices should be carefully chosen. In stretching yarn in the apparatus illustrated in the drawing by the preferred process described above, in which water is introduced into the chamber in contact with the yarn and g steam is introduced through an orifice surrounding the yarn inlet, the fluid drag to which the yarn is subjected is applied mainly by three fluid currents. These are- (l) The current of water flowing through 0121- go doc 80 in a direction opposite to that of the travel oi the yarn, v

(22 The current of water flowing through the conical shaped space in member 0 and out through the orifice i2,

(3) The current of steam flowing through the outlet id.

It is desirable to make the fluid drag opp n the travel of the yarn, i. e., that due to current (i), as low as possible and for this reason the so cross-section of the orifice i0 should be as small as possible having regard to the dimensions of the yarn being stretched. Further, in order to reduce the tension on the yarn in the stretching chamber as much as possible, fluid drag du to 40 current (2) should be greater than that due to current (1) and with this object in view the cross-section of orifice it through which the yarn enters the chamber should be larger than that of orifice ill. The ratio of the two cross-sections 50 which gives the best results will depend, upon the stretching conditions, particularly upon the orifice through orifice it it is to the steam pressure,

steam and water pressures, and is best determined by experiment. It should, however, be

borne in mind that the pressure drop through 55 i0 is to atmospheric pressure while which may be 30 or 35 lbs/sq. in. or more above atmospheric pressure. Consequently, in order that the fluid flow through l2 .should be sumcient 0 to produce a drag greater than that exerted by the flow through it, it is usually necessary to make the cross-section of orifice i2 substantially greater than that of orifice it, for example 2 or 3 times as great. 5 The size of the outlet it from the chamber is of less importance. Usually an orifice about the same size as that of orifice i2 is suitable.

Suitable diameters for the orifices are usually about 0.02" to 0.04." when single yarns or a 7 number of ends having a total denier of, for instance, 500 or 1000 are being treated. If the total denier is substantially greater then larger orifices will be necessary in order to allow the yarns to pass freely. For example, with yarns or slivers 70 vine deniers 0! 10,000 to 20,000, the diameter of the orifice i0 may vary from about 0.05" to 0.1" and those oi the'orlflces l2 and it from about 0.00" to 0.14". As a rough approximation it has been found that for diflerent yarn deniers the orifice diameters giving the bestresults are proportional to the square roots of the deniers.

The length of the treatment chamber depends upon the nature of the treatment and of the articles to be treated. For example, in stretching operations it is desirable to have a chamber 20 or 30" long when yarns of heavy deniers, such as 10,000 or 20,000 are to be stretched, while with lower denlers chambers oi, for example, 6", 9" or 12" in length are satisfactory.

The stretching conditions employed in using the novel apparatus are similar to those employed in the stretching, operations, described in the specifications referred to'above. Thepressure of th water entering the chamber is, however, higher, and preferably substantially higher, than that-of the steam used. The pressure diderence may, for; instance, be about 5 lbs. per square inch but usually better results are obtained if water is employed at a pressure of, for example, 10, 15 or lbs. per square inch higher than that of the steam. The temperature of the water is preferably low, for example from atmospheric temperature up to or C. The steam pressure employed will depend own the steam temperature required and this again will depend primarily upon the degree oi stretch and also to some extent on the particular type of yarn being stretched. For stretching yarns of acetone-soluble cellulose acetate to from 10 to 20 times their original length, which is usually the most desirable degree of stretch, steam temperatures of between l35 and 142C. are generally most suitable. Thus in such operations the steam pressure (gauge) will usually be between 30 and lbs. per square inch, and the water pressure between 35 and lbs. per square inch.

Stretching and other treatments of yarns and similar materials with fluid media may be carried out while thematerials are travelling in a horizontal plane or at an angle to the horizontah Particularadvanta'ges, however, are ob talned when the treatment is carried out with the injector and treatment chamber in a vertical posltion-or substantially so, so that materials travel vertically or substantially so. Such an arrangement reduces the floor space occupied by the apparatus and also renders the whole apparatus much more accessible to the operatives. When the operation in question is the stretching of yarns and similar materials of an organic derivative of cellulose we have found that upward stretching should be effected, much bet- ,ter results being obtained by this method than when the materials travel downwards during the operation. A further advantage of this method of stretching when wet steam is employed is that lower steam temperatures are required in order to obtain the optimum results.

On emerging from the treatment chamber the yarn may be passed round a roller situated above the exit from the chamber and from this roller down again to a take-up device. The distance which the yarn traverses between the exit from the treatment chamber to the take-up device will depend upon the nature of the treatment. the character of the materials and other factors. It may, for instance, be as little as 4" or 6" or-it may be considerably more, for example 24" or 36". Similar variations in the length or the path of The use of the apparatus according to the present invention has been described principally in relation to the stretching of yarns made of cellulose acetate in wet, steam, since it is for this purpose that the apparatus is of greatest importance. It will be appreciated, however. that its value is not confined to such an operation. It may be employed, ,for instance, in stretching yarns and similar materials of other organic dey rivatives of cellulose, e. g., cellulose propionate, butyrate, acetate-propionate and other esters,-

ethyl and propyl celluloses and other ethers and ether-esters of cellulose, e. g., hydroxy-ethyl cellulose acetate. The materials, particularly when they'have a basis of a cellulose ether, e. g., ethyl cellulose, may contain a plasticiser for the -cellulose derivative, e. g.,- castor oil, oleyl alcohol, vaseline or tri-cresyl phosphate, thus reducing the steam temperature required for any given degree of stretch. After stretching the plasticiser may be removed from the materials by treating them with a suitable solvent for the plasticiser. Further, the invention is applicable broadly to the stretching of yarns and similar materials, for example bristles, having a basis of organic derivatives of cellulose or other substances, particularly thermoplastic substances, e. g.-, polyamides or polyvinyl compounds, in stretch-assisting fluids, e. g., water or a solution of an organic solvent for the substance. Moreover, the invention is not confined to stretching operations but extends to other fluidtreatments of materials carried out during their passage through a substantially closed treatment chamber, e. g., saponiflcation and shrinking processes.

As has already been indicated, apparatus comprising an injector provided with means for feeding a fluid into the inlet is the most important form of apparatus according to the present invention, since it can function not only as an automatic threading-up device but also to prevent loss of treatment fluid through the inlet and the consequent backward drag on the materials. Moreover, as explained above, the introduction of water into the chamber in contact with the materials, which canbe effected with such a.

form of injector, is of great importance in connection with the stretching of the materials in wet steam.

arenas? matlcally threading-up the apparatus and for introducing treatment fluid uniformly around the materials under treatment.

Having described our invention, what we desire to secure by Letters Patent is:

1. Apparatus for the treatment of yarns and similar materials with fluids duringtheir passage from one point to another, which comprises a substantially closed treatment chamber, an in- However,-even if the injector is not provided with means for feeding a fluid into the inlet it is nevertheless of great value as a means for autolet for the materials and opposite thereto an outlet for the materials, said inlet comprising an outer member provided with a passage way for fluid and an inner member provided with an orifice for the passage of the materials, said inner and outer members being so shaped and spaced as to provide a. truncated-conical annular passage betweenthem communicatingwith the said passage way in the outer member and with its narrow end issuing into the treatment chamber, said truncated-conical passage being adapted to feed fluid directly into the treatment chamber around the said orifice and in the general direction of travel of the materials and thereby, in the absence from the apparatus of the materials, to induce a current of fluid through the said orifice so as to facilitate threading 0f the materials into the apparatus, said inner member comprising a passage way for fluid feeding into a substantially conical cavity provided at itsbroader end with an orifice for the entry of the materials into the cavity and at its narrower end with an orifice for the passage of the materials from the cavity into the treatment chamber, the said orifices having a cross section not substantially greater than that of the materials.

2. Apparatus according to claim 1 wherein the inner member of the inlet for the materials is movable with respect to the outer member so as to enable the width of the annular passage between them to be varied. I

THOMAS JACKSON. FRANK BRENTNALL HILL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,403,126 Lyth Jan. 10, 1922 1,871,100 Walton et al. Aug. 9, .1932 2,131,409 Nai Sept. 27, 1938 2,142,722 Dreyfus et al. Jan. 3, 1939 2,317,448 Dreyfus et al. Apr. 27, 1943 2,005,580 Ferre June 18, 1935 2,194,565 Moss Mar. 26, 1940 2,138,578 Hershberger Nov. 29, 1938 Country Date Great Britain July 11, 1942 Number 

